这是我的数据框：
RefactoringType RefactoringDetail
Pull Up Attribute "Pull Up Attribute protected steps : int from class blokusgame.mi.android.hazi.blokus.GameLogic.PlayerAlgorithm to class blokusgame.mi.android.hazi.blokus.GameLogic.Player"
Pull Up Attribute "Pull Up Attribute protected steps : int from class blokusgame.mi.android.hazi.blokus.GameLogic.PlayerAlgorithm to class blokusgame.mi.android.hazi.blokus.GameLogic.Player"
Pull Up Attribute "Pull Up Attribute protected steps : int from class blokusgame.mi.android.hazi.blokus.GameLogic.PlayerAlgorithm to class blokusgame.mi.android.hazi.blokus.GameLogic.Player"
Extract Method "Extract Method private getBestMove(moves ArrayList<Move>) :
Move extracted from public nextStep() : void in class blokusgame.mi.android.hazi.blokus.GameLogic.PlayerAlgorithm
Extract Method "Extract Method private getNLongMoves(n int) : ArrayList<Move> extracted from private getAllPossibleMoves() : ArrayList<Move> in class blokusgame.mi.android.hazi.blokus.GameLogic.PlayerAlgorithm"
Extract Method "Extract Method public getPoints() : ArrayList<Point> extracted from public equals(b Object) : boolean in class blokusgame.mi.android.hazi.blokus.GameLogic.Block"
Extract Method "Extract Method public getMin() : Point extracted from public getDimensions() : Point in class blokusgame.mi.android.hazi.blokus.GameLogic.Block"
Extract Method "Extract Method public getMax() : Point extracted from public getDimensions() : Point in class blokusgame.mi.android.hazi.blokus.GameLogic.Block"
Extract Method "Extract Method public normalize() : Block extracted from public equals(b Object) : boolean in class blokusgame.mi.android.hazi.blokus.GameLogic.Block"
Extract Method "Extract Method package setPlayer(player Player) : void extracted from protected onCreate(savedInstanceState Bundle) : void in class blokusgame.mi.android.hazi.blokus.MainActivity"
Extract Method "Extract Method public isPlaceable(block Block, pt Point) : boolean extracted from public isPlaceable(block Block, corners ArrayList<Point>, pt Point) : boolean in class blokusgame.mi.android.hazi.blokus.GameLogic.Map"
我需要提取第一个String“ class”之后的部分。我使用了这段代码
import pandas as pd
df = pd.read_csv('result_refactorings.csv', sep=';')
refactoring_details = df['RefactoringDetail']
print(refactoring_details)
a=refactoring_details.to_frame(name=refactoring_details)
a.RefactoringDetail.str.extract(r'class ([^ ]*)')
它没有返回包含NAN的所有行（从12行开始）的所有数据。我找不到问题 结果是：
0 blokusgame.mi.android.hazi.blokus.GameLogic.Pl...
1 blokusgame.mi.android.hazi.blokus.GameLogic.Pl...
2 blokusgame.mi.android.hazi.blokus.GameLogic.Pl...
3 blokusgame.mi.android.hazi.blokus.GameLogic.Pl...
4 blokusgame.mi.android.hazi.blokus.GameLogic.Pl...
5 blokusgame.mi.android.hazi.blokus.GameLogic.Block
6 blokusgame.mi.android.hazi.blokus.GameLogic.Block
7 blokusgame.mi.android.hazi.blokus.GameLogic.Block
8 blokusgame.mi.android.hazi.blokus.GameLogic.Block
9 blokusgame.mi.android.hazi.blokus.MainActivity
10 blokusgame.mi.android.hazi.blokus.GameLogic.Map
11 blokusgame.mi.android.hazi.blokus.GameLogic.Pl...
12 NaN
13 NaN
PS：在某些行中有两个类词，我需要在第一类之后的数据，然后将结果放入一个csv文件中
感谢帮助